Assuming that your site administrator has properly started the
postmaster process and authorized
you to use the database, you (as a user) may begin to start up
applications. As previously mentioned, you should add /usr/local/pgsql/bin to your shell search path. In
most cases, this is all you should have to do in terms of
preparation.

Two different styles of connections are supported. The site
administrator will have chosen to allow TCP/IP network connections
or will have restricted database access to local (same-machine)
socket connections only. These choices become significant if you
encounter problems in connecting to a database, since you will want
to confirm that you are choosing an allowed connection option.

If you get the following error message from a Postgres command (such as psql or createdb):